<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            background: linear-gradient(to top left,#ffe29f, #ffa99f, #ff719a);
            overflow: hidden;
        }

        .container{
            text-align: center;
            color: #fff;
        }

        .container h1{
            font-size: 60px;
            font-weight: bold;
            letter-spacing: 2px;
            margin-bottom:15px;
            transition: 1s ease-in-out;
        }
        .form{
            display: flex;
            flex-direction: column;
            align-items: center;
            position: relative;
            z-index: 2;
            opacity: 1;
            transition: opacity 0.5s;
        }

        .form input{
            outline: none;
            border: 1px solid rgba(255, 255, 255, 0.4);
            background-color: rgba(255, 255, 255, 0.2);
            width: 250px;
            padding: 10px 15px;
            border-radius:3px;
            margin: 0 auto 10px auto;
            text-align: center;
            color: #fff;
            font-size: 15px;
            transition: 0.25s;    
        }

        .form input ::placeholder{
            color: #fff;
            font-size: 14px;
            font-weight: 300;
        }

        .btn-login{
            outline: none;
            background-color: #fff;
            color: #ff719a;
            border: none ;
            width: 250px;
            padding: 10px 15px;
            border-radius: 3px;
            font-size: 15px;
            cursor: pointer;
            transition: 0.25s;
        }

        .form input:hover{
            background-color: rgba(255, 255, 255, 0.4);
        }

        .form input:focus{
            background-color: #fff;
            width: 300px;
            color: #ff719a;
        }

        .btn-login:hover{
            background-color: #f5f7f9;
        }

        .bg-squares{
            list-style: none;
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 1;
        }

        .bg-squares li{
            width: 40px;
            height: 40px;
            background-color: rgba(255, 255, 255, 0.15);
            position: absolute;
            bottom: -160px;
            animation: square 20s linear infinite;
        }

        .bg-squares li:nth-child(1){
            left: 10%;
        }

        .bg-squares li:nth-child(2){
            left: 20%;
            width: 80px;
            height: 80px;
            animation-delay: 2s;
            animation-duration: 17s;
        }

        .bg-squares li:nth-child(3){
            left: 25%;
            animation-delay: 4s;
        }
        
        .bg-squares li:nth-child(4){
            left: 40%;
            width: 60px;
            height: 60px;
            background-color: rgba(255, 255, 255, 0.25);
            animation-duration: 22s;
        }

        .bg-squares li:nth-child(5){
            left: 70%;
        }

        .bg-squares li:nth-child(6){
            left: 80%;
            width: 120px;
            height: 120px;
            background-color: rgba(255, 255, 255, 0.2);
            animation-delay: 3s;
        }

        .bg-squares li:nth-child(7){
            left: 32%;
            width: 160px;
            height: 160px;
            animation-delay: 7s;
        }

        .bg-squares li:nth-child(8){
            left: 55%;
            width: 20px;
            height: 20px;
            animation-delay: 15s;
            animation-duration: 40s;
        }

        .bg-squares li:nth-child(9){
            left: 25%;
            width: 10px;
            height: 10px;
            background-color: rgba(255, 255, 255, 0.3);
            animation-delay: 2s;
            animation-duration: 40s;
        }

        .bg-squares li:nth-child(10){
            left: 90%;
            width: 160px;
            height: 160px;
            animation-delay: 11s;
        }

        .container.success h1{
            transform: translateY(75px);
        }

        .container.success .form{
            opacity: 0;
            visibility: hidden;
        }

        @keyframes squares {
        0%{
            transform: translateY(0);
        }
        100% {
            transform: translateY(-120vh) rotate(600deg);
        }
    }


    </style>
</head>
<body>
    <div class="container">
        <h1>Welcome</h1>
        <div class="form">
            <input type="text" placeholder="您的账号">
            <input type="password" placeholder="您的密码">
            <button class="btn-login"> 登录</button>
        </div>
    </div>
    <ul class="bg-squares">
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>

    

</body>
</html>